Burton M. Onofrio

Myxopapillary ependymoma. A clinicopathologic and immunocytochemical study of 77 cases

The study involved 77 myxopapillary ependymomas of the spinal cord encountered during a 60‐year period (1924–1983). This variant of ependymoma was, with few exceptions, limited to the lumbosacral region, particularly the filum terminale. The male:female ratio was 1.7:1, and the mean age at diagnosis was 36.4 years (range, 6–82); at presentation, 15 (19%) of the patients were in the first two decades of life. The duration of symptoms ranged from 1 month to 30 years; the most frequent complaint was low‐back pain, and eight patients had undergone prior “disc surgery.” Generally, myelographic block was disclosed. Preoperative cerebrospinal fluid protein levels averaged 2462 mg/dl. Myxopapillary ependymomas are slow‐growing tumors that show no significant tendency to histologic dedifferentiation. Despite some variation in cytologic features and the presence of atypia and modest mitotic activity in most cases, the gross characteristics of the tumors appear to be of greater prognostic significance than the histologic features. Tumors that were encapsulated (25%) and amenable to intact, total surgical removal had a recurrence rate of 10%, whereas those that were removed either piecemeal (34%) or subtotally (41%) had recurrence rates of 19%. Overall survival, however, was more closely related to residual disease; total removal of tumor, whether intact (encapsulated) or piecemeal, resulted in longer survival (19 years) than did subtotal resection (14 years). Patients who died (6.5%) did so after a prolonged course marked by multiple recurrences. Radiotherapy may be of particular benefit to patients whose tumors are not amenable to intact total removal.

High Doses of Spinal Morphine Produce a Nonopiate Receptormediated Hyperesthesia: Clinical and Theoretic Implications

In rats with chronically implanted intrathecal catheters, high concentrations of morphine (3 μl of 50 mg/ml: 150 μg) yielded a reliable and striking syndrome of pain behavior that involved intermittent bouts of biting and scratching at the dermatomes innervated by levels of the spinal cord proximal to the catheter tip. In addition, during intervals between bouts of agitation, the animals displayed a clear, marked hyperesthesia where an otherwise innocuous stimuli (brush stroke) evoked significant signs of discomfort and consequent aggressive behavior. These effects were exaggerated rather than reversed by high doses of naltrexone. The effect, perfectly mimicked by a considerably lower dose of morphine-3-glucuronide (15 μg) or the glycine antagonist strychnine (30 μg), was not produced by equimolar concentrations of sodium sulfate, glucuronide, methadone, or sufentanil. In halothane-anesthetized cats, light brushing of the hindpaw and tail or low-intensity stimulation of the sciatic nerves resulted in prominent elevations in blood pressure and pupil diameter following the intrathecal administration of high concentrations (50 mg/ml; 0.1 ml) of morphine sulfate. This effect, exaggerated by naloxone, was produced by a lower concentration of intrathecal morphine-3-glucuronide (5 mg/ml; 0.1 ml) but not by intrathecal saline. These results suggest the possibility that the effects of high doses of morphine may be characterized by a nonopiate receptor-mediated effect that alters the coding of sensory information in the spinal cord. The authors speculate that high concentrations of spinal opiates, as may be employed in tolerant terminal-cancer patients, could exert an action that physiologically antagonizes the analgesic effects otherwise mediated by the action of morphine on the spinal opiate receptor.

Synovial Cysts of the Spine

A series of 13 patients with synovial or ganglion cysts of the spinal facet joints causing nerve root compression is reported. These cysts were found in both the cervical and the lumbar spine, and the anatomical location of each cyst corresponded to the patients signs and symptoms. In no case was there evidence of intervertebral disc abnormality found at operation. The patients ranged from 49 to 77 years of age and included 4 men and 9 women. Radiographic evidence of facet degenerative change and degenerative spondylolisthesis was frequently but not invariably noted. The extradural defects defined with positive contrast myelography or postmyelography computed tomographic scanning were usually posterior or posterolateral to the common dural sac and were misinterpreted as extruded discs in the majority of cases. Treatment consisted of laminectomy and surgical excision of cysts. All patients reported improvement or resolution of their presenting symptoms.

Comprehensive study of diagnosis and treatment of trigeminal neuralgia secondary to tumors

Among 5,058 patients seen at the Mayo Clinic from 1976 through 1990 for face pain, we diagnosed trigeminal neuralgia in 2,972. Tumors were causing the face pain in 296 patients. Sex and pain distributions paralleled those in idiopathic trigeminal neuralgia; however, patients with tumors causing trigeminal neuralgia were younger than those with idiopathic pain. Meningiomas and posterior fossa tumors were the most common. Neurologic deficits developed on follow-up evaluation in 47% of the patients, often precipitating further study and eventual diagnosis of the tumor. Delay in tumor diagnosis averaged 6.3 years. CT with contrast was the most frequently used initial diagnostic radiographic technique, detecting a tumor in 40 of 43 examinations. MRI was subsequently used to confirm and better delineate the tumor in five of five cases. Carbamazepine was the most effective drug for relieving trigeminal neuralgia, but relief was usually temporary. Of the surgical treatment options, total removal of the tumor was the most effective in completely relieving tic pain. In patients at high surgical risk, however, temporarily or permanently blocking afferent impulses with radiofrequency ablation, glycerol rhizotomy, or alcohol blocks was a good alternative to craniotomy.

Paraganglioma of the cauda equina region: Clinicopathologic study of 31 cases with special reference to immunocytology and infrastructure

Thirty‐one paragangliomas of the cauda equina region were studied (18 men and 13 women, ages 30–71 years [mean, 51 years]). Symptoms (1 day to 15 years in duration; mean, 48 months) included low back pain (87%), sensory/motor deficits (35%), urinary/fecal incontinence (13%), and paraplegia (6%). AH patients studied had some myelographic block. Cerebrospinal fluid protein level ranged from 56 to 7000 mg/dl (mean, 1109 mg/dl). Most tumors were limited to the filum terminale, although one also involved the conus medullaris and two clearly arose from a caudal nerve root. All but one were entirely intradural. The tumor was totally excised in 26 cases; these patients remain disease‐free. Of three patients whose tumors were excised subtotally, two received radiotherapy; the one non‐radiated patient died of tumor‐related complications. No autopsy was performed. One partially encapsulated tumor that had been subjected to biopsy and irradiation presented 1 year later with osseous invasion and retroperitoneal extension; 20 years after subtotal excision, this patient is alive but paraplegic. Morphologically, all tumors resembled paraganglioma at other sites. Cytologic atypia and mitotic activity generally were absent to mild. Fourteen (45%) cases showed ganglionic differentiation. All tumors tested were immunoreactive for neuron‐specific enolase and neurofilament protein, and most showed somatostatin or serotonin reactivity. S‐100 protein immunoreactivity was noted in sustentacular cells and, to a lesser extent, within chief cells and neurons. The authors conclude that paragangliomas are largely benign and encapsulated and respond to simple resection. When surgically feasible, gross total removal should be the goal of surgery. When subtotal resection is necessary or when local invasion leaves a question as to completeness of tumor removal, irradiation seems mandatory although far from guaranteeing prevention of recurrence. Biopsy alone is undesirable.

Retrospective consideration of the doses of morphine given intrathecally by chronic infusion in 163 patients by 19 physicians.

&NA; A retrospective, multi‐physician survey was carried out to examine the infusion concentrations of morphine delivered intrathecally by continuous infusion pumps placed to control pain. Replies from 19 physicians formed the basis for a population of 163 patients who received morphine by continuous infusion delivered by an Infusaid pump through a chronically implanted intrathecal catheter (N = 130 for pain of a metastatic origin; N = 3 for non‐metastatic pain; N = 30 undefined). These patients received a total of 3443 patient weeks of infusion. The median infusion duration was 13 weeks (± 1quartile; 5–24 weeks). Examination of the concentrations employed revealed that the maximally employed concentration was 1 mg/ml (885 patient weeks). Of the 163 patients, 151 patients received no concentration of morphine sulfate higher than 10 mg/ml. The highest reported concentrations used were around 35 mg/ml. No pathological sequelae related to the infusion of any dose of the opiates were reported. Cumulating the experience with morphine solutions of 8, 9 and 10 mg/ml reveals a total of 472 patient weeks in 29 patients. Analysis of the change in infusion dose over time in cancer pain patients revealed a prominent time‐dependent increase (N = 130) from 4.8 ± 0.4mg/day (N = 130) to 21 ± 9 mg/day at 52 weeks (N = 10; mean ± S.E.M). Though the group morphine utilization rose, examination of the patient population which was infused for periods in excess of 3 months indicated that 48% showed less than a 2‐fold increase in dose by 3 months.

Incidence of lumbar disc surgery. A population-based study in Olmsted County, Minnesota, 1950-1979.

Age- and sex-specific incidence rates of operation for suspected lumbar disc prolapse were determined for residents of Olmsted County, Minnesota, for the 30-year period 1950 through 1979. The incidence rate (adjusted to the age and sex distribution of the United States white population in 1980) was 52.3 per 100,000 person-years for all such operations and 46.3 per 100,000 person-years for initial operations. These rates remained fairly constant over the study period. A distinction was made between surgically proven and unproven cases of lumbar disc prolapse. Patients with a surgically proven lumbar disc prolapse had about 10 times the risk of another operation for disc prolapse within 10 years after the first operation compared with the general population.

Successful Management of Bilateral Carotid-Cavernous Fistulae with a Trans-sphenoidal Approach

A patient with traumatic bilateral carotid-cavernous fistulae was successfully treated by an entirely extracranial approach. The larger fistula on the left was exposed via a transethmoidal, trans-sphenoidal route and was directly opened and packed while the cavernous carotid artery was stented open by an intraluminal balloon catheter. The balloon catheter provided temporary hemostasis and was removed after the fistula had been packed. The left carotid artery remained patent, and the smaller fistula on the right was subsequently obliterated by a balloon catheter. The fistulae have remained cured, and the left internal carotid artery supplies the cerebral circulation.

Cervical Spondylotic Stenosis and Myelopathy: Evaluation With Computed Tomographic Myelography

OBJECTIVE To determine which components of cervical spondylosis are most frequently present in patients with myelopathy. DESIGN We reviewed the findings in 93 patients who underwent surgical decompression for cervical spondylotic myelopathy between January 1986 and December 1989 at Mayo Clinic Rochester. MATERIAL AND METHODS All 93 patients (72 men and 21 women) underwent computed tomographic (CT) myelography. In addition, magnetic resonance imaging scans were available in 25 patients, and plain CT scans were obtained in 2. RESULTS A review of CT myelograms revealed that all neurocompressive intraspinal spondylotic changes were reflected in the shape of the spinal cord. Among the 93 patients with myelopathy, the configuration of the spinal cord could be categorized into primarily three dominant types: A (severe encroachment that compressed the cord into the shape of a banana; N = 40), B (moderate encroachment that produced less prominent compression; N = 23), and C (moderate bilateral uncovertebral spurs; N = 12). As a comparison group, 30 patients with similar spinal cord deformities but without progressive myelopathy were analyzed. Correlation of the two groups showed that myelopathy was present in up to 98% of patients with type A spinal cord, in 75% with type B, and in 71% with type C. The findings on magnetic resonance imaging were similar to those on CT myelography, but the bony spondylotic components were less readily seen. CONCLUSION The precise pathophysiologic mechanism of myelopathy in spondylosis remains an enigma. Although the bulk of the data on our patients supports direct compression, we believe that the cause is multifactorial.

Hearing preservation after removal of acoustic neurinoma

Between January 1, 1978, and July 1, 1983, 149 patients underwent acoustic ncurinoma rcmovnl (151 procedures). Of these, 119 ears (118 patients) had had some degree of hearing on the affected side preoperatively, and in all of them the tumors had been removed by a posterior cranial fossa approach. Fourteen (12%) had measurable hearing preserved postoperatively — serviceable in eight cars and poor in six. The patients with preserved hearing had had their hearing loss for a shorter period, slightly better preoperative hearing levels, and a smaller tumor. The complications, morbidity, and mortality in this group were comparable to those in other series. It is concluded that preservation of hearing is a worthwhile goal that can be achieved without increased risk.